Originally Posted by Humbert
9 x 9 meters square would use 16 columns not 9.
You can easily do a 9 X 9 meter house with 9 footings and columns and it would be 80 square meters on the inside.
You would have 1 footing/column dead center of the square.
You can even build it 10 X 10 and use 9 columns AND use regular roofing steel if one opts for blue scope metal roofing. Ground beans need to be a bit more robust but no problem at all.